Less than 55 grain requires less than 1:9 twist. 55 would probably be better with 1:10. 1:9 is best on average for 55-62 grain. I lean to 1:8 for 62 gr. and 1:10/11 for 55. Less twist for less. 1:7 is specifically designed to handle up to 77 gr. NATO tracer rounds. I don't shoot those. Not a fan of 1:7 and with one I believe we really need to use 62+ gr. heads.

I shoot 75gr BTHP match bullets out of my 1-9 twist Savage 12 FLVSS with a 26" barrel,and always have.It is the absolute most accurate load that I've ever shot.I have most groups (5 Shots)when I'm on,shoot in the .24-.35 range,and have shot in the .16-.20 range a few times when everything was just right.
But the same gun really opens up when shooting 75gr AMax's,but they are a longer bullet than the BTHP's.
My RRA 20" Varminter with a 1-8 twist loves to shoot the 75gr AMax bullets.